Schema.org should have mappings to Wikidata terms where possible

[danbri]

From Lydia Pintscher in https://twitter.com/nightrose/status/558549091844886528

@danbri any issue to track progress on http://schema.org  mapping to Wikidata? 
Maybe even get people to help out?

Update 2016-01-26 - since the original post there have been some improvements at both Wikidata and Schema.org:

• Wikidata: mappings (exact, super/sub) from properties and (perhaps to a lesser extent in that the notion isn't so built-in) types to schema.org can be expressed within Wikidata.
• Wikidata now has a SPARQL endpoint at https://query.wikidata.org which is the most natural way of retrieving data; other explorations such as JSON dumps below are less important now.
• Schema.org has updated its extension mechanism and is encouraging both hosted and external extensions.
• D3-compatible RDFS JSON-LD is published from schema.org and can be used for visualization; this would also be a good model for getting an overview of Wikidata. See http://bl.ocks.org/danbri/1c121ea8bd2189cf411c for example visualization.
• Various notes towards using Wikidata as an extension language for Schema.org are explored towards the end of this issue, as are SPARQL queries for extracting Wikidata's structure and property metadata for use in mappings.

 Nearby

• List of Wikidata properties https://www.wikidata.org/wiki/Wikidata:List_of_properties/all
• SPARQL interface https://query.wikidata.org/

[danbri]

Notes from IRC,

• Example of a schema.org property marked as equiv to another: schema:description equivalentProperty dcterms:description. https://github.com/schemaorg/schemaorg/blob/master/data/schema.rdfa#L5696
• this info is currently exposed in schema.org per-term pages like view-source: http://schema.org/description e.g. as
• Wikidata RDF dumps (oldish?), http://tools.wmflabs.org/wikidata-exports/rdf/exports/20141013/
• Wikidata toolkit, https://www.mediawiki.org/wiki/Wikidata_Toolkit
• There are also JSON dumps, e.g. http://dumps.wikimedia.org/other/wikidata/20141215.json.gz

[lydiapintscher]

Here is how mapping can be done on the Wikidata side for example: https://www.wikidata.org/wiki/Property:P31

The JSON dumps are the best dumps.

[danbri]

• https://git.wikimedia.org/raw/mediawiki%2Fextensions%2FWikibase/master/docs%2Fjson.wiki
• https://www.wikidata.org/wiki/Wikidata:Database_download#JSON_dumps_.28recommended.29
• -> http://dumps.wikimedia.org/other/wikidata/
• -> http://dumps.wikimedia.org/other/wikidata/20150120.json.gz

[innovimax]

+1

[elf-pavlik]

happy to help here a little! I had chance to meet few people from Wikidata crew during 31C3 and remember that serving turtle also needs some fixing... but it already uses schema.org quite a lot!

$ curl http://www.wikidata.org/entity/Q80 -iL -H "Accept: text/turtle"

[danbri]

I went looking for the code that generates this. For those without turtle, an excerpt from running

curl http://www.wikidata.org/entity/Q42 -iL -H "Accept: text/turtle"

(full response is at https://gist.github.com/danbri/66616096d42e595376f6 )

[update]Hmm actually you can get it all in the browser without using content negotiation, just via suffixes:

• http://www.wikidata.org/wiki/Special:EntityData/Q42.ttl
• http://www.wikidata.org/wiki/Special:EntityData/Q42.nt
• http://www.wikidata.org/wiki/Special:EntityData/Q42.rdf

( edit! I have moved a big chunk of text to https://gist.github.com/danbri/181ff7763f479c397e10 - apologies to those who got accidental notifications due to the '@' symbol.)

This is great but also unfortunately "the easy part" in that these are fixed built-in properties that each Wikidata entry will always carry.

Looking around for relevant source code,

• https://meta.wikimedia.org/wiki/Wikidata/Development
• http://git.wikimedia.org/search/?s=schema.org&r=mediawiki/extensions/Wikibase&st=COMMIT
• http://git.wikimedia.org/blob/mediawiki%2Fextensions%2FWikibase/10729fd431938bc59333875b30855066c0f12f73/repo%2Fincludes%2Frdf%2FRdfBuilder.php#L253

It would be interesting to see how addEntityMetaData might be amended to exploit equivalentProperty information in Wikidata, at @lydiapintscher mentioned re https://www.wikidata.org/wiki/Property:P31

[ppKrauss]

I agree, "Schema.org should have mappings to Wikidata terms where possible". How to vote? or how to colaborate and/or check work in progress? There are a link about work in this issue?

[elf-pavlik]

@danbri please remember to fence code snippets with three backticks which can also include clue for syntax highlighting

```ttl
  code goes here @bg @dr @mr
  @prefix data: http://www.wikidata.org/wiki/Special:EntityData/ .
  @prefix schema: http://schema.org/ .
  no mentions using @foo

```

also see code tab in Examples of github markdown https://guides.github.com/features/mastering-markdown/#examples

[elf-pavlik]

@ppKrauss I think people would appreciate more machine readable mappings using owl:equivalentProperty etc.
e.g.

schemaorg/data/schema.rdfa

Line 5706 in d370e33

<link property="owl:equivalentProperty" href="http://purl.org/dc/terms/description"/>

IMO we could consider everything from subset of OWL used by RDFa Vocabulary Entailment
http://www.w3.org/TR/rdfa-syntax/#s_vocab_expansion

[ppKrauss]

@elf-pavlik thanks (!), so the issue now is only to add something as
<link property="owl:equivalentProperty" href="http://WikiDataURL"/>
in each rdf:Property and each rdfs:Class ... is it?

New suggestion: we may colaborate with an online interface or (initially) by a spreadsheet (ex. Excel) at github, with the columns wikidataID and Property or wikidataID and Class.